2x2 .120 on one end make a notch in each corner so all for sides can fold out about an 1in. then make a pie slice on the other end at the right length...
I used 2X3 and they are similar to Bigslim's, but mine were a bit simpler, I just cut the top section out at the rear to slide it over the rear rail. I also notched the sides so I could bend them to the angle to fit snugly on the rear and then welded up the notches.
same as blue missle, 1.5 x 3, .125 thick and if I remember correctly they are 43" long. Welded in of course. I made 3 pairs, one for me and two to sell.